Hello, I have a query on Ardupilot’s definition of ARSPD_FBW_MAX:
This is the definition from Arduplane parameter list:
“Maximum airspeed demanded in automatic throttle modes. Should be set slightly less than level flight speed at THR_MAX and also at least 50% above ARSPD_FBW_MAX to allow for accurate TECS altitude control.”
The definition from the TECS tuning page:
“This is the maximum airspeed (in metres/second) that the autopilot will use in auto-throttle modes. It should be set to the highest speed that the aircraft can achieve in level flight with the throttle set to THR_MAX. It must be sufficiently above the ARSPD_FBW_MIN value to allow the autopilot to accurately control altitude using airspeed (at least 50% above ARSPD_FBW_MIN is recommended). For electric aircraft, make sure this number is achievable at the end of flight when the battery voltage has reduced.”
For the parameter list, I suppose that “50% above ARSPD_FBW_MAX” is a typo (it should be ARSPD_FBW_MIN, otherwise it makes no sense). But how about the relationship to THR_MAX? The parameter list states that ARSPD_FBW_MAX should be slightly less than the level flight speed at THR_MAX, while the TECS documentation states that they should be equal. Does anybody know which definition is correct?